Control system



Aug. 11, 1931. D. L. LINDQUIST ET AL 1,318,486-

CONTROL SYSTEM Filed June 12, 1925 2 Sheets-Sheet 1 I 110ml LL,

a GWUZL N avwemtoj Patented Aug. 11, 1931 UNITED STATES PATENT OFFICE DAVID L. LINDQUIST, OF I-IARTSDALE, NEW YORK, AND GEORGE N. CRABBE, OF CRESS- KILL, NEW JERSEY, ASSIGNORS TO OTIS ELEVATOR COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY CONTROL SYSTEM Application filed June 12, 1925. Serial No. 36,648.

The invention relates to control systems and particularly to such systems arranged for the control of elevators.

In elevator systems it often occurs that the elevator car is not in use over an extended period of time. When the elevator motor is supplied with current from the generator of a prime mover generator set, these idle periods result in considerable power loss due to the continued operation of the prime mover.

One feature of the invention resides in automatically shutting down the prime mover generator set upon the elevator motor remalnlng idle for a predetermined period of time.

Another feature is to cause the restarting of the prime mover generator set in response to the operation of the means employed to start the elevator car.

Still another feature resides in preventing the operation of the elevator, motor so long as the strength of the elevator motor field is below a certain predetermined value.

Other features and advantages will become apparent from the following description, taken in connection with the accompanying drawings wherein one embodiment of the invention is illustrated as applied to an automatic push button elevator system and in which Figure 1 is a View in section, taken along line 11 of Figure 2, of a time element switching mechanism suitable for use in the system; t

Figure 2 is a view taken along line 2-2 10f Figural, with the motor omitted;

Figure 3 is a View in section, taken along line 33 of Figure 1; and

-Figure 4 is a simplified diagram of an automatic push button elevator system.

Referring first to Figures 1, 2 and 3, the

preferred form of time element switching, mechanism will be described. The various parts of the mechanism are mounted on the panel 11. The switch is operated by a motor 12. A coupling flange 13 is secured to the lower end of the motor shaft 4 as by a pin. This flange is connected in driving relation to a second coupling flange 15 as by means of a nut 23 and pin 19.

the pin 16. The flange 15 is secured by a pin to the vertical shaft 17. This shaft is supported by a bearing 18 formed on the supporting plate 20. A collar 21 is pinned to the shaft 17 below the bearing 18. Below the collar 21- is a worm 22, the worm being held in position on the shaft 17 by means of through the collar 21 by means of a key 24 formed on the collar, the key extending into a slot in the worm. The worm drives a worm gear 25 secured, as by a pin, to a horizontal shaft 26. This shaft is supported by a bearing formed in the hanger 27; On the side of the hanger opposite the worm gear, the shaft 26 is driving relation is effected between the collar 28 and another w-ornr30 provided on shaft 26 in a similar manner to that effected between collar 21 and worm 22. The worm 3O drives another worm gear 31 pinned to another vertical shaft 32. .A flange 33 is provided on shaft 32 above the supporting plate for retaining the shaft in position within the bearing 3 1 and therefore for retaining the driving relation between worm 30 and gear 31. The gearing below plate 20 is enclosed by an oil pan 35, the pan being secured to the plate as by means of screws 36.

A bell crank lever 37 is'pivotally mounted on the vertical shaft 32. The arm 38 of'the bell crank lever which extends toward the panel 11 is provided with a pin 40. An idler gear 41 is rotatably mounted on this pin, the idler being driven by means of a gear 42 pinned to shaft 32 above the lever 37. This idler gear is moved into operative engagement with a gear 43 by means of what may be termed a clutch magnet 44. The clutch magnet is secured to the plate 20, its mounting frame 45 being provided with depending arms 46 for pivotally supporting a bell crank lever 47. The stem 48 of the magnet plunger 50 extends through an aperture 51 in the horizontal arm 52 of the lever 47 and is provided at its lower end with a'washer 53 positioned by pin 54. A spring 55 is arranged on the stem between the washer and the horizontal arm 52. The Vertical arm 56 provided with a collar 28. A

This worm is driven x 68 secured to the of the lever 47 is connected by link 57 with the other arm 58 of hell crank lever 37.

The gear 43 is secured-to a bushing 60, the bushing being rotatably mounted on a pin 61 secured in plate 20. The bushing forms a guide for a torsion spring 62. One end of this spring is secured to plate 20 and the other end to the gear 43. The, gear 43 is provided with a plurality of apertures 63 arranged in a circle about the pin 61. Each aperture is threaded so as to receive a stop pin 64 and a trip pin 65, the stop pin being screwed into the desired aperture from the bottom of the gear and the trip pin from the top.

The trip pin 65 is arranged to engage a block 66, of insulating material, secured to the bottom side of the end of arm 67. The arm 67 is pivoted at its inner end on a pin bracket 70, being positioned by the washer 71 and pin 7 2. A second tor- -si0n spring 73 is arranged between the arm 67 and bracket 70, a guide 74 for the spring being formed on the arm 67. One end of the spring is secured to the arm and the other end to the bracket. Projections. 75 are formed on the inner end of arm 67 to formcontact lever 76 for the movable contact 77. This contact may be of any suitable construction, its stem 78 being provided with a nut 80 for securing the contact to the lever and for attaching the clip 81 for conductor 82. The movable contact normally engages a stationary contact 83, this latter contact being supported by a contact holder 84 secured to panel 11. The lower arm 85 of lever 76 is arranged to pivotally support the operating arm 86, an aperture being provided for receiving the pivot pin 87. The upper end of arm 86 is provided with lugs 88 and 89 for engaging the projection 90 on lever 76 to cause the separation and engagement of the switch contacts.

A tension spring 91 is secured at one end to a lug 92 formed on the {upper end of arm 86 and at the other end to a similar {arm 67.

The conductor 82 is provided at its other end with a clip 94 secured to one of the screws 95 provided for mounting the bracket 70 on the panel. This screw is provided with nuts 96 at the rear of the panel for connecting the switch in the system. Similarly, one of the lug 93 formed on the outer end of screws 97 for mounting the contact holder 84 .on the panel is provided with nuts 98 at the rear of the panel, also for connecting the switch in the system. Binding posts 100 are provided on the panel for connecting the operating motor and clutch magnet coil 103 in the system. Bolts 101 are for securing the supporting plate 20 to the panel. The por'- tion of the mechanism above the supporting plate is enclosed by a cover 102.

In operation, assume thatthe clutch magtops. a

The bracket 70 also pivotally supports the 43 are so positioned that, with the speed reduction obtained through the train of gears, each successive aperture represents an additional half minute in the time interval to be obtained. With the trip pin in the position illustrated, four minutes will elapse after the energization of the motor and clutch magnet coil before the switch contacts are separated. Toward the end of the four minute interval,the trip pin 65 engages the block 66 causing the outer end of arm 67 to move to the right as viewed in Figures 1 and 3. Continued movement of the arm causes the lug 93, and therefore the bottom end of spring 91, to approach the center line of arm 86. The tension of the spring is thus gradually increased. As the center line is reached and even passed, it will be seen from the illustration that thecenter line of the spring has not reached the pivot point for contact lever 76. Thus, the force of the spring still tends to keep the switch contacts in engagement, eliminating chattering and burning of the contacts. As the lug 93 passes the center line of arm 86, the spring 91 causes clockwise movement of the arm, it being noted that pressure is exerted to maintain the contacts in engagement until the center line of the spring passes the pivot point of lever 76. The upper end of the arm 86 gains in speed during this movement so that lug 88 strikes projection 90 a hammer blow, causing quick separation of the switch contacts 77, 83. Upon the separation of the contacts, the motor 12 and clutch magnet coil 103 are deenergized, as will be seen from later description. The plunger 50 of the clutch magnet drops by gravity and, aided by spring 55, strikes the arm 52 of lever 47 a hammer blow, insuring the disengagement of the idler gear 41 from gear 43. It is to be noted that the torsion springs 62 and 73 are wound up during the switch opening operation, spring 62 returning gear 43 to normal position upon the release of the idler gear 41. As this normal position is reached, he stop pin 64 engages a bumper 104, comprising for example a piece of felt 105 reinforced by projection 106 formed on plate 20, damping the stop. Torsion spring 73 overcomes the force of spring 91 as the trip pin 65 is withdrawn, causing the return of arm 86. As the arm moves back into its former position, lug strikes projection v switch.

,time after contacts of the switches 90, causing the reengagement of the switch contacts. It is believed obvious from the above desc'rlption that deenergization of the motor 12 and clutch magnet coil 103, at any theirenergization, causes the return of those parts, which have moved, to their normal position, regardless of the extent of movement or of the time that the deenergization occurs.

Reference may now be had-to Figure 4 which illustrates diagrammatically the particular application of the invention to a push button= elevator control system. N 0 attempt is made in this figure to show the coils and contacts of the electromagnetic switches in their associated positions, a straight diagram being employed wherein the coils and CODtlCllSfOf the various switches are separated in such manner as to render the circuits'involved relatively simple. For a clearer understanding of the invention, the stationary are illustrated in cross section. The electromagnetic switches ave been designated as follows A-Potcntial switch,

BUp direction switch CDown direction switch, D-lUp accelerating relay, E-Down accelerating relay, FFirst accelerating switch, G-Second accelerating switch, H-Brake relay, IHall button non-interference switch, il -Hall button non-interference relay, K-Driving motor accelerating switch, lib-Driving motor running switch, M-Driving motor starting relay, NDriving motor auxiliary starting rela C-Maintaining relay, PTime 'rclay, Q'-l\1inimum current field'relay, R-First floor switch, S-Second floor switch, T-Third floor switch, RRFirst floor relay, SSSecond floor relay, TT-Third floor relay.

Throughout the description which fol lows, these letters, in addition to the usual reference numerals, are applied to the parts of the above enumerated switches. Fpr eX- ample, contacts B' 231 are contacts on the up direction switch, while actuating coil A 190 is the coil that operates the potential The electromagnetic switches are all shown in their deenergized positions.

The elevator car is raised and lowered by the elevator motor 110. Current is supplied to the motor 110 by a variable voltage direct current generator 111 driven as by a squirrel cage type alternating current motor 112. 113, 114 and 115 are the alternating current mains, resistances 116 being arranged in the mains sume that a for the purpose of starting the driving motor. An exciter 117, driven by motor 112, is employed to supply current for the separately excited fields, 118 for the generator and 120 for the elevator motor, and for certain of the control circuits. The armature of the exciter is designated by the numeral 121. The generator is provided also with a series field 122. The exciter is provided with a shunt field 123 and a series field 124. Discharge resistances 125 and 126 are provided for the separately excited fields of the generator and elevator motor respectively. A resistance 127 is arranged in shunt to the generator series field. A resistance, divided into sections 128 and 130, is provided for controlling the strength of the generator field 118 and therefore the voltage applied to the elevator motor armature. 131' is the release coil for the elevator motor electromagnetic brake. Coil 131 is provided with a discharge resistance 132. A push button for each floor is provided in the car, these buttons to be hereinafter referred to as car buttons. An up push button and a down push button are provided at each intermediate fioor, only one intermediate floor being included for convenience of description. An up push button is provided at the first floor and a down push button at the third or top floor. These latter buttons, as distinguished from car buttons, will be hereinafter referred to as hall buttons. A safety switch 133 also is arranged in the car. A floor controller, designated as a whole by the numeral 135, is provided for causing the operation of certain of the electromagnetic switches to slow down and stop the car at the landings. Control switches 136 and 137 are provided on the control panel. Various safety switches and door and gate contacts may be employed, reference to which may be had in connection with the description of the various circuits. It will be assumed that the motor generator set is not in operation, that control switches 136 and 137 and safety switch 133 are in closed positions and that the door contacts and gate contacts are in engagement. 6

With the car at rest at the first floor, as-

prospective passenger desires to be carried from the first to the second floor.

Upon the closure of the gate and door and thepushing of the second floor car button 140, a circuit iscompleted for the second floor relay actuating coil SS 141 and the driving motor starting relay actuating coil M 148. This circuit may be traced from alternating current main 114, by Way of line 142 throughcontacts J 163 of the hall button non-interference relay, car button 140, coil SS 141,. coil M 148, contacts H 150 of the brake relay and one of the pairs of gate contacts 134, tomain 115. Relay SS, upon operation, causes the engagement of contacts SS 151, preparing a circuit for for the second floor switch actuating coil S 152 and the engagement of contacts SS 153,

I actuating coils SS 141 and M 148. Relay M,

preparing the maintaining circuit for the upon operation, causes the engagement of contacts M 154, completing the circuit'for the driving motor auxiliary starting relay actuating coil N 155. This circuit maybe traced from main 113, b way of line 156 through contacts M 154, time switch contacts77, 83, coil N 155 and control "switch 136, to main 114. The relay N, upon operation, causes the engagement of contacts N 157, N 158 and N 160. The engagement of contacts N 157 completes the maintaining circuit for coils,SS 141 and M 148. .This circuit may be traced irom main 114, line 142, by way of line 161 through hall button non-interference relay actuating coil J 162, contacts N 157 and contacts SS 153, back to line 142 through coil SS 141, coil M 148, contacts H 150 and gate contacts 134, to

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main 115. Thus it will be seen that this maintaining circuit is established immediately the button is pushed, permitting the immediate release of the button. The relay J, upon operation, causes the separation of contacts J 144 and contacts J 163 and the engagement of contacts J 164. The engagement of contacts J 164 prepares a circuit for the hall but ton non-interference switch actuating coil 1 165. The separation of contacts J 144 breaks the circuit for the hall buttons, rendering them inefi'ective. The separation of contacts J 163 breaks the circuit for the car buttons, rendering them inefi'ective.

The engagement of contacts N 158 complates the circuit for the actuating coil K 166 of the driving motor starting switch and the engagement of contacts N 160 firepares the circuit for the actuating coil 167 of the driving motor running switch. The circuit for coil K 166 may be traced from main 113, by way of line 168 through contacts N, 158, coilK 166 and contacts L 170, to main 114. Thus the switch K operates immediately a button is pushed, the operation of the switch causing the engagement of power contacts K 171, K 172 and K 173, connecting the stator of the driving motor 112 to the alternating current mains through resistances 116. Thus the driving motor is started in operation. The engagement of contacts K 172 and K 173 also completes the circuit for coil L 167. The circuit for coilL 167 may now be traced from main 114, contacts K 172, one of the resistances 116, by way of line 174 through contacts-N 160 and coil L 167, another of the resistances 116, contacts K 173, to main 115. The switch L, however, does not operateimmediately, the voltage applied to its actuating coil being of low value due to the high potential drop over resistances 116 during the starting of the driving motor. As this motor approaches full speed, the current in the stator windings is reduced, raising the voltage across coil L 167, causing the operation of switch L. This switch, upon operation, causes theengagement of power contacts L 175, L 176 and L 177 to by-pass resistances 116 and connect the driving motor directly to the mains. Also the switch L causes the engagement of contacts L 178 to prepare the circuit for the maintaining relay.

actuating coil 180 and the separation of contacts L170 to deenergize coil K 166 and of contacts L 181 to remove the short circuit around the actuating coil Q, 182 of the minimum current field relay. The switch K drops out separating contacts K 171, K 17 2 and K 173 to disconnect resistances 116 from the 182 does not receive current until the exciter E;J.M. F. is built up to substantially full.

value. 'As has been stated previously, the exciter supplies current to the field 120 of the elevator motor .110, the field circuit being from the left hand exciter terminal 183, line 184, byway of line 185 through field 120 and coil Q 182, line 186 to theright hand exciter terminal 187. Until the elevator motor field builds up, the field having a certain time constant,-the current supplied to coil Q, 182 is of insufi'icient value to cause the operation of the relay Q. As soon as the elevator motor field builds up to substantially full value, relay Q operates to cause the engagement of contacts Q 188. The circuit for the potential switch actuating coil A 190 is completed upon the engagement of contacts Q 188 and may be traced from terminal 183, "line 184, by way of line 191 through switch 137, coil A 190, contacts Q, 188, various safety switches (indicated by legend) and safety-switch 133, line 186, to terminal 187. With such an arrangement, it is impossible for coil A. 190 to be energized :and therefore impossible 'for the potential switch to be in operated condition with the strength of the elevator motor field'below a certain predetermined value. In this manner, injury to the system, such as might re-., sult from dangerous speeds of the elevator motor, is prevented. In order that this may be clearly seen, assume that the system is not provided with the relay Q. and the contacts L 181. Upon starting up, due to itsitinae constant, the elevator motor field'builds up much more slowly than theE. M. F. of the exciter.

Thus the potential switch would operate before the elevator motor field built up and the elevator motor would start up on a weak field and would tend to run away. By providing the system with the minimum current field relay Q, starting the elevator motor ona weak field in this manner is prevented since the motor field current must be of sufiicient value to effect the operation of the relay. As

a further example, assume that the system is provided with the minimum current field relay but not with the contacts L 181. Upon disconnection of the driving motor 112 from the mains after the system has been in 0 ration, the current through coil Q 182 would reduce slowly due to the time constant of the motor field. Thus if a push button should be operated to cause the reconnection of the driving motor to the mains before the relay Q dropped out to break the potential switch coil circuit, again the elevator motor might be caused to operate with a weak field due to the exciter E. M. F. building up relatively rapidly. By providing the system with contacts L 181, starting the elevator motor on a weak field in this manner is prevented since coil Q 182 is short-circuited and therefore contacts Q 188 are separated immediately the driving motor running switch L drops out.

Assuming then that contacts Q 188 are in engagement and that coil A 190 is energized, the potential switch operates to cause the engagement of contacts A 192 and A 193. With the other pair of gate contacts 194 and door contacts195in engagement, these "latter contacts representing all the door contacts in series relation, the engagement of contacts A 192 and A 193 completes the circuit for the maintaining relay actuating coil 0 180 and prepares the circuit for the generator fieldv 118 and certain other control circuits. The

circuit for coil 0 180 may be traced from terminal 183, by way of line 184 through contacts A 192, by Way of line 205 through coil 0 180 and contacts L 178, by way of line 186, through contacts A 193, to terminal 187. The relay 0, upon operation, causes the engagement of contacts 0 208 in the circuit for the motor 12 and clutch magnet coil 103 ofthe time element switching mechanism and the engagement of contacts 0 210 to by-pass starting relay contacts M 154 in the circuit for the'drivmg motor auxiliary starting relay actuating coil N 155. Rela 0 also causes the engagement of contacts 8 209 completing the circuit for the hall button non-inter ference switch actuating coil I 165 and a circuit for the second floor switch actuating coil S 152 and the time relay actuating coil P 196. The circuit for coil I 165 may be traced from terminal 183, b way of line 184'through contacts A 192, 6 y way of line 197 through gate contacts 194, door contacts 195 and contacts 0 209 by way of line 198 through resistance 200, contacts J 164 and, coil I 165, line 201, line202, safety switch 133, line 191, line 186, ,to terminal 187. The circuit for coils S 152 and I P 196 may be traced from terminal 183 to line 198 as above traced, by way of line 203 through resistance way of line 202 through coil S 152 and coil P196, to terminal 187 as above traced. Y

The switch I, upon operation, causes the separation of contacts I 145 in line 143 to the hall buttons and the engagement of contacts I 206 to by-pas's contacts J 164 in the circuit for its actuating coil I 165. The relay P, upon operation, causes the separation of contacts P 207 in the circuit forthe motor 12 and clutch magnet coil 103 of the time switch mechanism. Thus'the engagement of contacts O 208 is substantially without effect during the starting operation as the circuit for motor 12, and clutch magnet coil 103 is immediately broken by the separation of contacts P 207. The switch S, upon operation, causes the engagement of pleting the circuit for the brake relay actuating coil H 212 and the up direction switch actuating coil B 213, and the engagement of contacts S 214, completing the circuit for the up accelerating relay actuating coil D 215. (The circuit for coils H 212 and B 213 may be traced from terminal 183, by way of line 184 through contacts A 192, by way of line 197 through gate contacts 194, door contacts 195, contacts 0 209, coil H 212, down direction switch contacts C 216, coil B 213 and floor controller switch 217, by way of line 218 through contacts S 211, b way of line 202 through coils S 152 and 196, to terminal 187 as previously traced. The .circuit for coil D 215 may be traced from terminal 183, by way of line 184 through contacts A 192, by way of line 197 through gate contacts 194, door contacts 195 and contacts 0 209, by way of line 220 through resistance 221, by way of line 222 through down accelerating relay contacts E 223, coil D 215, floor controller switch 224 and contacts S 214, by way of line 202 to terminal 187 as previously traced. It is to be noted that a maintaining circuit is thus established for coils S 152 and P 196.

. The brake relay H, upon operation, causes the separation of contacts H 225 and H 150 and the engagement of contacts H 226 and H 227. Contacts H 227 will be referred to later. The engagement of contacts H 226 completes the circuit for the brake release coil 131, the circuit being traced from termi' nal 183, by way of line 184 through contacts A 192, by way of line 228 through coil 131 and contacts H 226, by way of line 186 through contacts A 193, to terminal187. The separation of contacts H 150 breaks the maintaining circuit comprising coils M 148, SS 141 and 162. The relay M, upon dropping out,,causes the separation of contacts contacts S 211, com- M 154 in the circuit for coil N 155, the coil contacts H 225 disconnects the generator field v 118,from the generator armature.

The direction switch B operates simultaneously with the brake relay H. and causes the separation of contacts B 230 and the engagement of contacts B 231 and B 232. The separation of contacts B 230 prevents the unwarranted energization of thedown directionswitch actuating coil C 233, the contacts B 230 and G 2l6 serving as electrical interlocks in the manner well understood in theart.

The engagement of contacts B 231 and B 232 completes the circuit for the generator field 118. This circuit may be traced from the motor field being energized and current being supplied from armature 236 of the generator 111 to the armature 237 of the elevator motor 110, due to the enerator'field' 118 being energized, the e evator motor starts.

The upaccelerating relay\ D operates along wit relay Hand switch B to cause the separation of contacts D 238 and the engagement of contacts D 240. The separation of contacts D 238 prevents the unwarranted energization of down accelerating relay coil E 241, contacts D 238 and E 22.3 serving as-electricalinterlocks for coils E 241 and D 215. The engagement of contacts D 240 along with the engagement of contacts H 227 completed the circuit for thefirst accelerating switch actuating coil F 242. This circuit may be tracedirom terminal 183, by way oflline 124 through contacts A 192, by way of line 2 3 through contacts H 227, oil F 242, reactance 244 and resistance 245, ine- 246, by way of line 247 through contacts D 240, line 248,'by Way of line 202, to terminal 187 as previously traced. The switch F does not operate, however, upon the immediate energization or: itsactuating coil, its ac- .tion being delayed by the reactance 244. Upon operation, contacts F 250 enga short-eircuiting resistance section 128 in t e circuit for enerator field 118. Thus the generator E .F. is increased, causing the elevator motor to run at a faster speed. Also contacts F 251 engage, completing the circuit for the second accelerating switch actuating coil G 252. This circuit may be traced from terminal 183, by way of line 184 through contacts A 192, by way of line 243 through contacts 227, by way of line 246 through coil G 252, reactance 253, con

tacts F 251 and resistance 254, to terminal 187 as previously traced. As in the case of switch F, switch G is retarded in its operation by reactance 25.3. The reactances 244 and 253 thus provide time elements for the operation of the accelerating switches. Switch G, upon operation, causes the engagement of contacts G 255 too short-circuit resistance section 130 in the circuit for generator field 118, increasing the generator E. M. F. and causing the elevator motor to accelerate to full speed.

Although the manner of efiecting the operation is not shown, it is to be understood that the floorcontroller 135 is arranged to operate in unison with the elevator car. Thusas the car approaches the second floor, the contact bridge is moved off the contacts of the floor controller switch 224, breaking tlie circuit for coil D 215. Relay D, upon dropping out, causes the separation of contacts D 240, breaking the circuit for thecoils of the accelerating switches F and G, and the engagement of contacts D 238-in preparation for the next starting operation. The switch G drops out immediately due to the factthat its actuating coil G 252 discharges into a high resistance circuit comprising resistances 254,

245 and 256. Switch G, upon dropping out,

causes the separation of contacts G 255, rein serting resistance section 130 in series with" generator field 118, thus reducing the speed of the elevator motor. The switch F, how- Shortly before the car reaches the second floor, the contact bridge is moved off the contacts of the floor controller switch 217, breaking the circuit for coils H 212, B 213, S 152 and P 196. The second floor switch S, upon dropping out, causes the separation of its contacts S 211 and S 214 in preparation for the next starting operation. The time relay P, upon dropping out causes the reengagement of its contacts P 2 7, completing the circut for the motor 12 and clutch ma et coil 103 of the time switch mechanism. 's circuit may be traced from terminal 183, by way of line 184 through contacts A192, by way of line 201 throu h armature 257 and field 258 of motor 12, cl iitch magnet coil 103, contacts 0 208 and contacts P 207, line 202, to terminal 187 as previously traced. The motor 12 starts and the clutch magnet causes the engagement of the idler gear 41 with gear 43,

the. time switch mechanism thus starting in operation. The brake rela H, upon dropping out, causes the separatlon of contactsH 227 in preparation for the next starting oporation and of contacts H 226, breaking the circuit for the brake release coil 131 and the reengagement of contacts H 150 in preparation for the next starting operation and of contacts H 225, reconnecting the generator field 118 to the generator armature. The polarity of this latter connection is such that the generator armature sends current through the field in such direction as to oppose the flux which produces the generator E. M. F., thus tending to destroy the residual flux of the generator field. Up direction switch B, dropping out along with relay H, causes the separation of contacts B 231 and B 232 and the engagement of contacts B 230. The engagement of contacts B 230 is in preparation for the next starting operation. The separation of contacts B 231 and B 232 disconnects the generator field 118 from lines 184 and 186, the field being simultaneously connected to the generator armature by the engagement of contacts H 225 as explained above. Thus the generator field 118 being disconnected from the exciter and the brake being applied due to the deenergization of the release coil 131, the car is brought to rest at the second floor landing. The circuit for coil 1 165 is broken upon separation of the gate and door contacts 194 and 195, resulting in the separation of contacts I 206 and the engagement of contacts I 145 in preparation for the next starting operation.

Assume now that the passenger has left the car and-that no other buttons are pushed. At the end of the four minute period, it being assumed again for purposes of description that the time switch mechanism is set for four minutes, this mechanism operates to separate contacts 77, 83, breaking the circuit for the driving motor auxiliary starting relay coil N 155. Relay N, upon dropping out, causes the separation of contacts N 157, N 158 and N 160. The separation of contacts N 157 and N 158 is in preparation for the next starting operation. The separation of contacts N 160 deenergizes coil L 167 of the driving motor running switch. Switch L, upon dropping out, causes the separation; of power contacts L 175, L 176 and L 177, disconnecting the driving motor from the alternating current mains. Switch L also causes the separation of contacts L 178, breaking the circuit for the maintaining relay actuating coil 0 180 and the engagement of contacts L 170 in pre aration for the next starting operation an contacts L 181, short-circuiting the minimum current field relay coil Q, 182. The relay 0, upon dropping out, causes the separation of contacts 0 208, O 209 and O 210. The se aration of contacts 0 209 is in preparation or the next starting operation. The separation of contacts 0 210 also is in preparationfor the next starting operation, the circuit for coil N 155 having been broken by time switch contacts 77, 83 as above set forth. The separation of contacts 0 208 breaks the circuit for motor 12 and clutch magnet coil 103 of the time switch mechanism, the parts of the mechanism being restored to their initial position as previously set forth. The time switch contacts 77, 83, therefore, reengage, the reengagement being without efiect at this time as contacts 0 210 and contacts'M 154 are separated. Relay Q, upon dropping out, causes the separation of contacts Q 188, breaking the circuit for the potential switch coil A 190. The potential switch contacts A 192 and A 193, upon separation, break the common line-s 184 and 186 for the control circuits and'generator field 118, preparing the system for the next starting operation. In this manner, the stand-by losses of the motor generator set are reduced. This arrangement'acts to stop the motor generator set if for any reason the car is stopped an unusually long time during regular service as well as to prevent the motor generator set from running all night.

With the motor generator set shut down, the system is started in operation in response to the pushing of a button in the same mannor as previously described. For convenience of further description however, it will be assumed that a prospective passenger pushed the first floor hall button 260-before the four minute period had elapsed. A circuit is thus completed for actuating coil RR 261 of the first floor relay. 1 This circuit may be traced from alternating current main 114, line 142, by way of line 143 through contacts 'J 144, contacts I 145 and resistance 146, hall button 260, line 262, by way of line 263 through coil RR 261, back to line 142 through coil M 148, contacts H 150 and gate contacts 134, to main 115. The operation of relay M to cause the engagement of its contacts M 154' is without particular effect at this time as the circuit for coil N 155 is being maintained by contacts 0 210 and contacts 77, 83. Relay RR, upon operation, causes the engagement of contacts RR 264 to establish a maintaining circuit including coil J 162 for its actuating coil RR 261 and coil M 148 and the engagement of contacts RR 265 to complete a circuit for the actuating coil R-266 of the first floor switch and coil P 196 of the time relay. It is believed that the circuit for coils R 266 and P 196 will be obvious from the circuit previously traced for coils S 152 and P 196. Bela J and switch I, the actuating coil I 165 of w ich is energized in response to the oper- I ation of relay J, operate in the same manner as previously described.

The time relay P operates to separate its contacts P 207, breaking the circuit for the -motor 12 and clutch magnet coil 103 of the causes the engagement of contacts R 267, completing the circuit for the down direction switch actuating coil C 233, and of contacts R 268, completing the circuitfor the downv accelerating relay actuating'coiLE 241. The

circuit for coil 0 233 may be traced from terof line 184 through contacts A 192, by way of line197 through gate contacts 194, door contacts 195, contacts 0 209 and coil H 212, by way of line 270 through contacts B 230, coil G 233, floor controller switch 271 (now bridged) and contacts R 267, by way of line 27 2 through coil R 266, by way of line 202 through coil P 196, to terminal 187 as previously traced. The circuit for coil E 241 may be traced from terminal 183, by way of line 184 through contacts A 192, by way of line 197 through gate contacts 194, door contacts 195 and contacts 0 209, by way minal 183, by way 2 of line 220 through resistance 221, by way of line 273 through contacts D 238, coil E 241, floor controller switch 27 4 (now bridged) and contacts R 268, by way of line 272 to terminal 187 as above traced. The down direction switch G causes the separation of contacts C 216 corresponding to up direction switch contacts B 230 and the engagement of contacts C 27 5 and G 27 6 corresponding to contacts B 231 and B 232 respectively. The down accelerating relay causes the separation of contacts E 223 corresponding to up acoelerating relay contacts D 238 and the engagement of contacts E 277 corresponding to contacts D 240. Further than this it is believed that the description of starting the car in the down direction and stopping it at the first floor will be obvious from previous description.

In order that other parts of the system, not specifically designated, may be ascertained, the third floor relay actuating coil has'been designated TT 278 and its cont'acts'TT 280 and TT 281, and the third floor switch actuating coil has been designated T 282 and its 9 contacts '1 283 and T 284. The first and third floor car buttons have been designated 285 and 286 respectively. The down second floor hall button has been designated 287, the up second floor-hall .button 288, and the third floor hall button 290. i e

It is to be-understood that the timing arrangement is equally applicable for the control of other types of prime movers employed for driving the further understood that the invention may be employed with all its advantages in car switch controlled elevator systems or in other forms of push button'controlled systems.

As many changes could be made in the above arrangement and many apparently widely tion could be made without departing from the scope thereof, it is intended that all matter contained in the above description or generator 111. It is to be.

diilerent embodiments of the inven-' shown in the accompanying drawings shall be said driving means, and means for preventing the starting of the motor so long as the current in the field winding is below a predetermined value regardless of the time which elapses between the operation of the start and stop means to stop said driving means and the operation of the start and stop means to again start said driving means.-

2. In a control system, a motor having a field winding, a generator for supplying current to said winding, means for driving said generator, means for starting and stopping said driving means, means responsive to the current in said field winding and operable upon said current reaching a redetermined value during the starting of the driving means to control the starting of said motor,v

and means, responsive to the operation of the starting and stopping means driving means, for preventing the maintaining of the field winding current responsive to stop the means in operated condition in response to the current in said field winding. 3.- In a control system, a motor having a field winding, a generator for supplying currentto the armature of said motor, a secon generator for supplying current to the field winding of said motor, a driving motor for said generators, a source of power for said driving motor, ping the driving motor, means responsive to the current in said field winding and operable upon said current reaching a predetermined value during starting of the driving motor to control the starting of the first motor, and means, responsive to the operation of the first named means to stop the driving motor, for preventing the maintaining of the second named means in operated-condition by the current'in said field winding.

4.'In a control system, a motor having a field winding, a generator for supplying current to the armature of said motor, said gen-' erator having a field winding, a second generator connected tothe motor field winding for supplying current thereto, means for connecting the second generator also to said generator field winding for supplying current thereto, a second motor for driving said generators, a source of power for the second means for starting and stopmotor, means responsive to the current in the motor field winding for controlling the operation of the first named means, and means operable upon the disconnection of said second 1 motor from said source for deenergizing the second named means regardless of the current in said motor field winding.

5. In a control system, a motor having a erator connected to the for supplying current thereto, means for con-- field winding, a generator for supplyin current to the armature of said motor, sai generator having a field winding, a second enerator connected to the motor field win for supplying current thereto, means for con.- nectlng the second generator also to said generator field winding for supplying current thereto, a second motor for driving said generators, a source of power for the second motor, means responsive to the current in the motor field winding for controlling the operation of said first named means, means for disconnecting said second -motor from said source, and means responsive to the operation of the third included means for rendering the second included means ineffective.

' 6. In a control system, a motor having a field winding, a generator for supplyin current to the armature of saidmotor, said generator having a field winding, a second genmotor .ficld winding necting the second generator also to sa'd generator field winding for supplying o rrent thereto, a second motor for driving said generators,' a source of power for the second motor, electromagnetic means, having its opcrating winding in circuit with the motor field winding, for controlling the operation of the first named means, means for disconnecting said second motor from said source, and means responsive to the operation of the third included means, .forshort-circuiting the winding of said electromagnetic means.

7. In a control system, a motor, a generator for supplying current to said motor,

means for driving said generator, a source of power for sald driving means, means for causing the stopping of said motor, andmeans responsive to the operation of the second named means for discontinuing the su 'ply of power to said driving means upon t e expiration of a predetermined time interval after the operation of the second named means, said last included means comprising means for varying said time interval.

8. In a control system, a motor, a generator for supplying current to said motor, a

driving motor for said generator, a source of power for said driving motor, control means, means responsive to the operation of said control means for causing the connection of the driving motor to its source and thereafter the starting of the first motor, means for causing the stopping of thefirst motor, means responsive to the operation of the third named means for causing the disconnection of the and means responsive to the disconnection of driving motor from its source upon them:- piration ofa predetermined time interval after the operation of the third named means,

the driving motor from its source for rstoring the fourth named means to its initial condition. In a control system, a motor, a generator for supplying current to said-motor, a driving motor for said generator, a source of j power for the driving motor, means for cong nectmg the driving motor to its source, means responsive to the operation of the first named means to disconnect the drivin motor from itsisource, for restoring the ourth named means to its initial condition. 7

10. In a control system, a motor, a generator for supplying current to said motor, a

second 'motor for driving said generator, a

source of power for said driving motor, mea for causing the starting of the first motor, means for causing the stopping of the first motor, switching mechanism comprisin contacts for causing the disconnectlon 0 said driving motor from said source, said switching-mechanism further comprising movable means adapted upon movement for a predetermined period of time to operate said contacts, electromagnetic means adapted upon 'energization to cause the movement of said 7 movable means and means for returning said movable means to initial position upon deenergization of said electromagnetic means, and. means responsive to the operation of the second named means for causing the energization of the electromagnetic means and responsive to the operation of the first named means within said time period after the energization of-the electromagnetic means for causing the deenergization of said electromagnetic means.

ator for supplying current to the motor, a second motor for driving the generator, a source of power for the second motor, control means,

means responsive, to the operation of-said control means for establishing starting con- 11. In a-control system, a motor, a gener-.

third named means for 'causingthestarting of the first motor.

12. In a control system, a generator havlng a field winding, a source of current therefor, means for connecting said winding to said source, a plurality of control means, each for causing the operation of the first named means to connect the winding to the source, a driving motor. for said generator, a source of power for the driving motor, and means for disconnecting the driving motor from its source only upon the e iration of a predetermined time interval a r the operation of the first named means to disconnect said winding from its source, provided no other of said control means are operated.

13. In a control system, a motor, a generator for supplying current to the armature of said motor, a field winding for said generator, a source of current therefor, means for connecting said winding to said source, a plurality of control means, each for causing the operation of the first named means to connect said winding to said source, means for causing the operation of the first named means to disconnect the winding from said source, a driving motor for said generator, a source of power for the driving motor, and means responsive to the operation of the second named means for causing the disconnection of the driving motor from its source upon the expiration of a predetermined time interval after the operation of the second named means, provided no other of said control means are operated.

14. In a control system, a generator having a field winding, a source of current therefor, means for connecting said winding to. said source, means for-causing the operation of the first named means to connect said winding to said source, means for causing the operation of the first named means to disconnect said winding from said source, a driving motor for said generator, a source of power for the driving motor, switching means adapted upon the operation for a pre-' determined period of time to cause the disconnection of said motor from its source of power, electromagnetic means adapted upon energlzation to cause the operation of the fourth named means, and means responsive to the operation of the third named means for causing the energization of said electromagnetic means and responsive to the operation of the second named means for causing the deenergization of said electromagnetic means. v

15. In an elevator control system, a hoisting motor for the elevator car, a generator for supplying power to said hoisting motor, said generator having a field winding, a driving motor for said generator, a source of power for said drivin'g motor, a plurality of controls, one for each of a plurality of landings, means responsive to the operation of any one of said controls for controlling the energization of said field winding to efiect the suppply and discontinuation of the supply of power from said generator to said hoisting motor, and means formaintaining said driving motor connected to said source only until the expiration of a predetermined time interval after an operation of said field winding control means to deenergize said field winding, provided none of said'controls are to be responded to before said time interval expires and for thereupon disconnecting said driving motor from said source.

16. In an elevator control system, a hoisting motor for the elevator car, a generator for supplying power to said hoisting motor, said generator having a field winding, a driving motor for said generator, a source of power for said driving motor, a plurality of controls, one for each of a plurality of landings, means responsive to the operation of any one of said controls for controlling the energization of said field winding to effect the supply and discontinuation of the supply of power from said generator to said hoisting motor, means for causing said driving motor to be disconnected from said source upon the expiration of a predetermined time interval after an operation of said field winding control means to deenergize said field winding, provided none of said controls is operated within said time interval, and means for rendering said disconnecting means ineffective to cause the disconnection of said driving motor from said source in the event that one of said controls is operated within said time interval.

17. In a control system for an elevator car, amotor for raising and lowering said car, a generator for supplying current to the armature of the motor, said generator having a field winding, a second generator for supplying current to said field winding, means for connecting said field winding to said second generator, a second motor for driving said generators, a source of power for the second motor, means for connecting the second motor to the source, a plurality of switches for each floor, means responsive to the operation of any of said switches for causing the operation of the second named means to connect the second motor to the source and for causing the operation of the first named means to connect said field winding to the second generator, means for causing the operation of the first named means to disconnect said field winding from the second generator so as to cause the car to stop at the floor corresponding to said switch operated, and means, responsive to the operation of the fourth named means, for causing the operation of the second named means to disconnect the second motor from the source upon the expiration of a predetermined time interval, provided-no other of said switches are operated.

In testimony whereof, we have signed our, names to this specification.

DAVID L. LINDQUIST. GEORGE N. CRABBE. 

